deallocvt - deallocate unused virtual terminals
deallocvt [ N1 N2 ... ]
If given no argument, the program deallocvt deallocates kernel memory
and data structures for all unused virtual terminals. If arguments Ni
are given, only TTY’s /dev/ttyNi are deallocated.
A virtual terminal is unused if it is not the foreground console, and
no process has it open for reading or writing, and no text has been
selected on its screen.
chvt(1), openvt(1).